Improved Breakdown Strength in (Ba<Subscript>0.6</Subscript>Sr<Subscript>0.4</Subscript>)<Subscript>0.85</Subscript>Bi<Subscript>0.1</Subscript>TiO<Subscript>3</Subscript> Ceramics with Addition of CaZrO<Subscript>3</Subscript> for Energy Storage Application

(Ba_0.6Sr_0.4)_0.85Bi_0.1TiO₃ ceramics doped with x wt%CaZrO₃ (x= 0-10) were synthesized by solid-state reaction method. The effects of CaZrO₃ amount on the dielectric properties and structure of (Ba_0.6Sr_0.4)_0.85Bi_0.1TiO₃ ceramics were investigated. X-ray diffraction results indicated a pure cubic perovskite structure for all samples and that the lattice parameter increased till x=5 and then slightly decreased. A homogenous microstructure was observed with the addition of CaZrO₃. Dielectric measurements revealed a relaxor-like characteristic for all samples and that the diffusivity γ reached the maximum value of 1.78 at x=5. With the addition of CaZrO₃, the dielectric constant dependence on electric field was weakened, insulation resistivity enhanced and dielectric breakdown strength improved obviously and reached 19.9 kV/mm at x=7.5. In virtue of low dielectric loss (tan δ<0.001 5), moderate dielectric constant (ε_r >1 500) and high breakdown strength (E_b >17.5 kV/mm), the CaZrO₃ doped (Ba_0.6Sr_0.4)_0.85Bi_0.1TiO₃ ceramic is a potential candidate material for high power electric applications.     

Synthesis of Nanostructured PbO@C Composite Derived from Spent Lead‐Acid Battery for Next‐Generation Lead‐Carbon Battery

Lead‐carbon batteries could provide better performance on high‐rate partial‐state‐of‐charge (HRPSoC) cycles than lead‐acid batteries (LABs), making them promising for the new‐generation of hybrid electric vehicles. The addition of carbon allotropes to the negative active material (NAM) could induce a significant improvement to the battery performance. Herein, an environmentally friendly strategy is demonstrated to prepare lead oxide and carbon (PbO@C) composite by pyrolyzing the lead citrate precursor derived from the spent lead paste of LABs. When the PbO@C composite is used as an additive to the NAM of lead‐carbon batteries, the utilization efficiency of the NAM is improved from 56.9% to 72.5%, and the cycle life of the cell in HRPSoC is tremendously extended by four times compared with the control one. The enhancement in battery performance is attributed to the hydrophilic carbon in the composite, which acts as a 3D electroosmotic pump facilitating electrolyte diffusion, and hindering the tendency to excess sulfation during the HRPSoC operation. This proposed research provides a sustainable and scalable strategy to recycle the discarded/spent LABs into high‐performance lead‐carbon batteries.     

降低MTBE产品硫含量的探讨

催化液化气来料硫醇硫大幅上涨,在MTBE装置无脱硫单元时,为满足汽油调和对硫含量的要求。采取强化液化气脱硫措施,调整碱液置换量、溶剂油注入量、空气注入量等多种手段,将MTBE硫含量降至可控范围。     

基于遗传模拟退火算法的Otsu图像分割研究

针对目前基本遗传算法在优化图像分割算法中存在的易于早熟、陷入局部最优的不足,以最大类间方差函数为适应度函数,提出了一种基于改进遗传算法的图像阈值分割算法.对交叉、变异算子进行自适应改进,同时将模拟退火算法融入到遗传算法中,使得对个体的评价更合理,既能克服种群退化现象,又改善算法的全局搜索能力,避免遗传算法陷入局部最优.实验结果显示,与Otsu图像分割法以及基于遗传算法的图像分割方法相比,使用该方法得出的阈值范围更加稳定,执行效率更高,在图像分割中获得的分割效果更佳.     

DNA微阵列图象信息的自动提取

微阵列图象分析是分子生物学中DNA微阵列杂交实验数据测定过程的一个重要部分。其目的是将微阵列图象中大量象素灰度信息简化为微阵列靶点的信号值。该文介绍了一种对DNA微阵列图象信息进行自动提取的方法,使用此方法完全不需要人为操作,可避免操作者主观性对实验的影响,提高数据提取的效率和可重复性。其关键步骤包括:图象滤波,图象灰度信息提取,微阵列间距确定,靶点定位和靶点信号值计算。实验结果表明使用此算法提取DNA微阵列图象信息具有重复性好、效率高和分析准确的特点。     

Effect of Annealing on Ferroelectric Properties of Bi3.25La0.75Ti3O12 Thin Films Prepared by the Sol-gel Method

Bi_3.25La_0.75Ti₃O₁₂(BLT) thin films were prepared on Pt/Ti/SiO₂/Si substrate by the sol-gel method. The effect of annealing on their structures and ferroelectric properties was investigated. The XRD patterns indicate that the BLT films annealed at different temperatures are randomly orientated and the single perovskite phase is obtained at 550°C. The remnant polarization increases and the coercive field decreases with the annealing temperature increasing. The leakage current density of the BLT films annealed at 700°C is about 5.8×10⁻⁸ Al cm² at the electric field of 250 kV/cm. Funded by the National Natural Science Foundation of China (No. 90407023)     

Room-Temperature Colossal Magnetoresistance in Terraced Single-Layer Graphene

Disorder-induced magnetoresistance (MR) effect is quadratic at low perpendicular magnetic fields and linear at high fields. This effect is technologically appealing, especially in 2D materials such as graphene, since it offers potential applications in magnetic sensors with nanoscale spatial resolution. However, it is a great challenge to realize a graphene magnetic sensor based on this effect because of the difficulty in controlling the spatial distribution of disorder and enhancing the MR sensitivity in the single-layer regime. Here, a room-temperature colossal MR of up to 5000% at 9 T is reported in terraced single-layer graphene. By laminating single-layer graphene on a terraced substrate, such as TiO₂-terminated SrTiO₃, a universal one order of magnitude enhancement in the MR compared to conventional single-layer graphene devices is demonstrated. Strikingly, a colossal MR of >1000% is also achieved in the terraced graphene even at a high carrier density of ≈10¹² cm⁻². Systematic studies of the MR of single-layer graphene on various oxide- and non-oxide-based terraced surfaces demonstrate that the terraced structure is the dominant factor driving the MR enhancement. The results open a new route for tailoring the physical property of 2D materials by engineering the strain through a terraced substrate.     

烟草青枯菌FQY_4基因组中原噬菌体生物信息学分析

为了解青枯菌(ralstonia solanacearum)基因组中原噬菌体和噬菌体元件的信息,在烟草青枯菌FQY_4全基因组序列的基础上,分析了FQY_4染色体上的原噬菌体,结果显示FQY_4染色体上有1个具有完整噬菌体特征的原噬菌体,3个噬菌体元件。比较青枯菌GMI1000和FQY_4中的原噬菌体的序列信息,结果显示它们具有一定的相似性,其中青枯菌FQY_4的原噬菌体-2与噬菌体φRSA1的相似度为82%,它们有40个编码基因高度同源,相似度为99%以上。这些信息可为青枯菌原噬菌体的多样性分析,噬菌体和青枯菌的协同进化研究奠定基础。     

基于FPGA的嵌入式系统设计

提出了一种基于FPGA(现场可编程门阵列)和软核CPU的嵌入式系统设计的新方法。FPGA芯片选用A ltera公司的Cyclone系列芯片作为处理器,配合A ltera公司的NIOS软核嵌入式处理器构成整个系统的核心;操作系统采用μC/OS嵌入式系统,并移植到FPGA平台上;外围添加USB接口作为扩展接口,使用Cypress公司的EZ_USB系列芯片;整个系统以FPGA和NIOS为中心进行设计,外围接口包括JTAG、串口、USB口等。给出了系统硬件架构以及与USB芯片的接口应用电路。     

冗余金属填充对化学机械抛光的平坦性影响研究

在深亚微米大规模集成电路制造过程中,化学机械抛光已经被广泛用来实现大范围的平坦性。化学机械抛光后的形貌非常依赖版图的样式,并且在芯片上会有很大的波动。然而,由于器件结构分布的不均匀,化学机械抛光会导致金属层的凹陷和电解质的侵蚀。解决这种现象的方法之一便是插入冗余金属来实现给定层的均匀性。本文使用中科院EDA中心开发的化学机械抛光模拟器,分析了冗余填充的尺寸,密度和形状之类的参数对化学机械抛光后表面平坦性的影响。